The Active Denial System (ADS) is a non-lethal, directed-energy weapon developed by the U.S. military. It is a strong millimeter-wave transmitter primarily used for crowd control (the “goodbye effect”). Some ADS systems such as HPEM ADS are also used to disable vehicles. Informally, the weapon is also called pain ray.
The main idea is basically a microwave mounted on top of a Humvee. If you express yourself against the establishment, they will issue you “burn waves”.